Induction-coil



No. 620,027. Patented Feb. 2|, I899.

M. E. FULD. 2

INDUCTION COIL.

(Application filed Dec. 7, 1898.) (N0 Modal.) 2 Sheets-Sheet I.

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INDUCTION COIL.

(Application filed Dec. 7, 1898.) (No Model.)

2 Sheets-Sheet 2.

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UNITED STATES PATENT OFFICE.

MANES E. FULD, OF BALTIMORE, MARYLAND.

INDUCTION-COIL.

SPECIFICATION forming part of Letters Patent No. 620,027, dated February 21, 1899.

Application filed December 7, 1898. Serial No. 698,572. (No model.) I

To (t/ZZ whom it may concern.-

Be it known that I, MANES E. FULD, a citizen of the United States, residing at Baltimore, State of Maryland, have invented certain new and useful Improvements in Induction-Coils; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to improvements in induotion-coils, and more especially to that class of induction-coils known as medical coils, and the object of my invention is to greatly increase the efficieney of inductioncoils by a construction which is both simple and comparatively inexpensive. By my said invention I am, moreover, enabled to greatly increase the effect or induced current of a given induction-coil without materially increasing its size. This is particularly advantageous with respect to medical coils, Where it is desirable to make the apparatus as small as possible consistent with eliiciency in order that the apparatus may be the more readily transported. I accomplish this object by inserting between the core of the coil and the primary and secondary coils metal which is a good conductor of magnetic lines of force. It has been proven by repeated tests that an induction-coil thus constructed will give an induced current several times as great as a coil of the same size without my improvement. It is also a characteristic of coils con structed according to my invention that they do not have the injurious eitect upon the nerves of the patient as do coils of the usual type for a given intensity of current.

To more fully describe my said invention, reference will be had to the accompanying drawings, in which similar parts are represented by similar letters throughout the several views.

Figure 1 represents a transverse vertical section of my improved induction-coil, taken along the line 1 1, Fig. 2, and looking in the direction of the arrow. Fig. 2 represents a central longitudinal sectional view of the same, taken along the line 2 2, Fig. 2 5 and Fig. 3 is a fragmentary perspective View, partly in section, of the bobbin-tube, showing how the iron ribbon and insulation are wound thereon. Fig. 4 represents a central longitudinal sectional view of another form of induction-coil embodying the principle of my invention. Fig. 5 represents in side elevation the core, iron wrappin g, and metal sheath of the coil shown in Fig. 4; and Fig. 6 represents a cross-section of the same,taken along the line 6 6, Fig. 6.

In the accompanying drawings, A represents the bobbin, composed of any suitable insulating materialsuch, for example, as Wood, vulcanized fiber, hard rubber, pasteboard, and the like. The tube a of the bobbin may be either integral with the bobbin ends or detachably connected to them, as is sometimes done, and which will be perfectly obvious to anyone skilled in the art; but in all cases the tube is composed of insulating material. The bobbin is provided with the usual soft-iron core B, which, as is obvious, may be either solid or composed of a bundle of softiron Wires or constructed in any other suitable way, the construction of the core proper forming no part of my present invention. Next to the bobbin-tube is wound one or more layers'of sheet-iron or ferrotype-ribbon O, with insulating material D separating each convolution of the ribbon and wound upon the outside thereof, as shown. The ribbon C may be composed of one piece or divided into sections either in the direction of the axis of the core or at right angles thereto, or it may consist of a narrower ribbon than that shown, when it maybe wound on the bobbin spirally. Instead of the ribbon C insulated iron wire may be used. The insulation D may be paper, mica, cloth, or any desirable insulating material or preparation.

On top of the insulation which covers the ribbon O are wound the primary and secondary coils E and F, respectively.

The amount of insulation between the ribbon O and the primary and secondary coils may obviously be varied at will. It is also obvious that the method of starting and winding the ribbon O and the insulation D on the bobbin may be varied, but all the While keeping the ribbon thoroughly insulated from the core, from the primary and secondary coils, and from itself; but my invention is not confined alone to the form of coil above shown and described. In Figs. 4, 5, and 6 I have shown a coil embodying my invention, but diiliering from the form shown in the preceding figures principally in that it employs a sheath-regulator and does away with the necessity of wrapping the sheet-iron on the bobbin or spool proper. According to this form of my invention the central iron core B is inserted in a small wooden or other insulating-material casing A and around the outside of this casing is wrapped the sheet-iron or ferrotype O, which is insulated by the layers of insulating material D. The insulation D is wrapped around the outside of the sheet-iron O and securely glued thereto, so that both are rigidly secured to the casingA The tube a of the bobbin A is bored out to receive the casing A and core 13, with the bore reduced, as at a into which part one end of the casing A fits tight-1y.

A brass or copper regulating tube or sheath G slips over the sheet-iron and core and into the bobbin-tube, as shown. This sheath is the ordinary regulating-sheath of medical coils and operates to increase or diminish the effect of the coil by sliding it out or into the coil, as is well understood. The primary and seeondarycoils Eand Fare wound upon the bobbin-core as usual. By the above described construction, the same results are obtained as by the form of coils first described, and at the same time obviating the necessity of winding the sheet-iron on the bobbin proper, as has been already noted.

My invention is capable of other obvious modifications which will suggest themselves to those skilled in the art and which may be made without departing from the spirit of my invention; but

hat I do claim, and desire to secure by Letters Patent of the United States, is-

1. An induction-coil having insulated iron wrapped upon the bobbin-tube and the primary and secondary coils wound upon the said insulated iron, substantially as described.

In an induction-coil, the combination with an iron core, of a tube of insulating material surrounding said core, insulated iron carried upon and surrounding said tube, and the primary and secondary coils surrounding said insulated iron, substantially as described.

In an induction-coil, the combination with an iron core, of a tube of insulating material surrounding said core, insulated sheetiron carried upon and surrounding said core and the primary and secondary coils wound outside of the insulated sheet-iron, substantially as described.

at. In an induction-coil, the combination with the bobbin, of an iron core carried therein, one or more layers of insulated iron carried next to the bobbin, and the primary and secondary coils wound upon said insulated iron, substantially as described.

5. In an induction-coil, the combination with the bobbin, of a central iron core carried thereby, one or more layers of insulated sheetiron wound upon the tube of said bobbin, and the primary and secondary coils wound upon said insulated sheet-iron, substantially as described.

6. In an induction-coil, the combination with an iron core, of a tube of insulating material surrounding said core and next to the same, insulated iron carried upon and surrounding said tube, a bobbin with the said core, tube and iron carried within the tube thereof, a sheath-regulator adapted to inelose the said insulated iron and core and slide within said bobbin-tube, and the primary and secondary coils wound upon the said bobbintube, substantially as described.

7. An induction-coil having a central core, insulated iron surrounding said core and the primary and secondary coils surrounding said insulated iron, substantially as described.

In testimony whereof I affix my signature in presence of two witnesses.

MANES E. FULD.

Vitnesses:

GEO. W. HAULENBEEK, JULIUS W. STUART. 

